1. Field of the Invention
The present invention is directed to a drive arrangement comprising a drive shaft, a coupling device such as a hydrodynamic coupling device, and a coupling arrangement for connecting the drive shaft to the coupling device for transmission of force, wherein the coupling arrangement has a first toothing arrangement connectable with the drive shaft and a second toothing arrangement connectable with the coupling device and wherein the first toothing arrangement engages the second toothing arrangement when the drive shaft and coupling device are coupled for transmission of force.
2. Description of the Related Art
German reference DE 198 48 253 A1 discloses a known drive arrangement including a drive shaft and a torque converter to be coupled for common rotation. In this known arrangement, a torque-transmitting connection is made between the drive shaft and the torque converter, or a housing of the same, by a coupling arrangement with two toothing arrangements mesh with one another. Further, a guide pin is arranged in the center of the housing of the torque converter which engages in a guide opening formed in the drive shaft so that there is a further force-transmitting connection between the drive shaft and the torque converter for transmitting centering forces. That is, radial forces occurring between the torque converter and the drive shaft due to axial offsets or wobbling movement are contained in the region of the guide pin or guide recess.
A problem with this type of known arrangement is that the assembly of the total system is made difficult by the fact that the toothing arrangements as well as the guide pin and guide recess must be brought into respective engagement with one another and the region in which these subassemblies are located after assembly is generally covered by a transmission housing so that it is almost impossible to view the regions that must be brought into engagement with one another.
It is an object of the present invention to develop a drive arrangement including a drive shaft and a coupling device such that overcomes the problems of the prior art and is easy to assemble.
According to the present invention, this object is met by a drive arrangement comprising a drive shaft, a coupling device such as a hydrodynamic coupling device, and a coupling arrangement for connecting the drive shaft with the coupling device for the transmission of force. The coupling arrangement has a first toothing arrangement connectable with the drive shaft so that the first toothing arrangement is fixed with respect to rotation relative to the drive shaft and a second toothing arrangement connectable with the coupling device so that the second toothing arrangement is fixed with respect to rotation relative to the coupling device. The first toothing arrangement engages the second toothing arrangement when the drive shaft and coupling device are coupled for the transmission of force.
In this regard, it is further provided that the drive shaft and the coupling device are connectable with one another solely by the coupling arrangement for the transmission of force.
The present invention is based on the insight that the use of a guide projection of the type mentioned above is not compulsory. The essential forces, i.e., the driving forces, acting in circumferential direction are transmitted through the coupling arrangement. When radial forces occur between the drive shaft and the coupling device, these radial forces are parallel to the transmission of driving force in first and second circumferential regions located opposite one another with respect to the axis of rotation and are orthogonal to the transmission of driving force in third and fourth circumferential regions that are offset by 90xc2x0 relative to the first and second circumferential regions. The first and second circumferential regions mentioned above, which have already been formed for the transmission of the appreciably greater driving forces, can absorb the radial forces which pretension the coupling device and the drive shaft with respect to one another because a large force transmission capacity has already been provided in this direction. Accordingly, the guide projection and the corresponding recess in the drive shaft are not required and may be dispensed with so that only the toothing arrangement needs to be engaged during the assembly process. Therefore, it is not necessary according to the present invention to ensure that the guide projection is also suitably guided into the guide recess.
To provide a coupling between the drive shaft and coupling device that is substantially free from axial forces, the first toothing arrangement or the second toothing arrangement may comprise an internal toothing and the other respective toothing arrangement may comprise an external toothing.
Furthermore, the first toothing arrangement and the second toothing arrangement may be pretensioned in mutual engagement during engagement of the first and second too thing arrangements.
In a preferred embodiment of the coupling device, at least one of the first and second toothing arrangement comprises a plurality of successive toothing segments in other of the first and second respective toothing arrangements during engagement of the first and second toothing arrangements.
To achieve the required pretensioning force without having to provide additional pretensioning members, the toothing segments may comprise at least one curvature area pretensioned relative to the other one of the first and second toothing arrangements by springing elasticity. In a preferred embodiment, the toothing segments comprise a plurality of curvature areas. The toothing segments are preferably constructed as leaf springs for this purpose.
To provide the above-mentioned transmission of forces in the circumferential directionxe2x80x94driving force as well as radial offsetting forcexe2x80x94it is suggested that the toothing segments have a greater material thickness in circumferential direction than in a region of the same which is deformable in a springing-elastic manner.
The coupling device according to the present invention may comprise a hydrodynamic torque converter or a fluid coupling.